/* ===========================
   CSS Reset & Base Styles
   =========================== */

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

:root {
  /* Color Palette */
  --primary-color: #2563eb;
  --primary-hover: #1d4ed8;
  --secondary-color: #64748b;
  --secondary-hover: #475569;
  --danger-color: #dc2626;
  --danger-hover: #b91c1c;
  --success-color: #16a34a;
  --warning-color: #ea580c;
  
  /* Status Colors */
  --available-color: #10b981;
  --occupied-color: #f59e0b;
  --available-bg: #d1fae5;
  --occupied-bg: #fef3c7;
  
  /* Neutral Colors */
  --bg-color: #f8fafc;
  --surface-color: #ffffff;
  --border-color: #e2e8f0;
  --text-primary: #1e293b;
  --text-secondary: #64748b;
  --text-light: #94a3b8;
  
  /* Shadows */
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
  
  /* Spacing */
  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 1.5rem;
  --spacing-xl: 2rem;
  --spacing-2xl: 3rem;
  
  /* Border Radius */
  --radius-sm: 0.25rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;
  
  /* Transitions */
  --transition-fast: 150ms ease-in-out;
  --transition-normal: 250ms ease-in-out;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen',
    'Ubuntu', 'Cantarell', 'Fira Sans', 'Droid Sans', 'Helvetica Neue', sans-serif;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  background-color: var(--bg-color);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
}

/* ===========================
   Header Styles
   =========================== */

header {
  background-color: var(--surface-color);
  border-bottom: 1px solid var(--border-color);
  padding: var(--spacing-lg) var(--spacing-xl);
  box-shadow: var(--shadow-sm);
  display: flex;
  justify-content: space-between;
  align-items: center;
  position: sticky;
  top: 0;
  z-index: 100;
}

header h1 {
  font-size: 1.75rem;
  font-weight: 700;
  color: var(--text-primary);
}

/* ===========================
   Button Styles
   =========================== */

.btn {
  padding: 0.625rem 1.25rem;
  border: none;
  border-radius: var(--radius-md);
  font-size: 0.875rem;
  font-weight: 600;
  cursor: pointer;
  transition: all var(--transition-fast);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-sm);
  text-decoration: none;
  outline: none;
}

.btn:focus-visible {
  outline: 2px solid var(--primary-color);
  outline-offset: 2px;
}

.btn-primary {
  background-color: var(--primary-color);
  color: white;
}

.btn-primary:hover:not(:disabled) {
  background-color: var(--primary-hover);
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

.btn-secondary {
  background-color: var(--secondary-color);
  color: white;
}

.btn-secondary:hover:not(:disabled) {
  background-color: var(--secondary-hover);
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

.btn-danger {
  background-color: var(--danger-color);
  color: white;
}

.btn-danger:hover:not(:disabled) {
  background-color: var(--danger-hover);
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

.btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

/* ===========================
   Main Layout
   =========================== */

main {
  display: grid;
  grid-template-columns: 1fr 400px;
  gap: var(--spacing-xl);
  padding: var(--spacing-xl);
  max-width: 1600px;
  margin: 0 auto;
}

/* ===========================
   Room Grid Section
   =========================== */

.room-grid-section {
  min-width: 0;
}

.room-grid-section h2 {
  font-size: 1.5rem;
  font-weight: 700;
  margin-bottom: var(--spacing-lg);
  color: var(--text-primary);
}

.room-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
  gap: var(--spacing-lg);
}

/* ===========================
   Room Card Styles
   =========================== */

.room-card {
  background-color: var(--surface-color);
  border: 2px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: var(--spacing-lg);
  cursor: pointer;
  transition: all var(--transition-normal);
  position: relative;
  overflow: hidden;
}

.room-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
  border-color: var(--primary-color);
}

.room-card.selected {
  border-color: var(--primary-color);
  box-shadow: var(--shadow-md);
  background-color: #eff6ff;
}

.room-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 4px;
  transition: background-color var(--transition-fast);
}

.room-card.available::before {
  background-color: var(--available-color);
}

.room-card.occupied::before {
  background-color: var(--occupied-color);
}

.room-number {
  font-size: 1.75rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: var(--spacing-sm);
}

.room-status {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-xs);
  font-size: 0.875rem;
  font-weight: 600;
  padding: 0.25rem 0.75rem;
  border-radius: var(--radius-md);
  margin-bottom: var(--spacing-sm);
}

.room-status.available {
  background-color: var(--available-bg);
  color: var(--available-color);
}

.room-status.occupied {
  background-color: var(--occupied-bg);
  color: var(--occupied-color);
}

.room-status::before {
  content: '';
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background-color: currentColor;
}

.room-guest {
  font-size: 0.875rem;
  color: var(--text-secondary);
  margin-top: var(--spacing-sm);
  display: flex;
  flex-direction: column;
  gap: var(--spacing-xs);
}

.room-guest-name {
  font-weight: 500;
  color: var(--text-primary);
}

/* ===========================
   Room Details Panel
   =========================== */

.room-details-panel {
  background-color: var(--surface-color);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: var(--spacing-xl);
  box-shadow: var(--shadow-md);
  position: sticky;
  top: calc(80px + var(--spacing-xl));
  max-height: calc(100vh - 80px - var(--spacing-xl) * 2);
  overflow-y: auto;
  transition: opacity var(--transition-normal), transform var(--transition-normal);
}

.room-details-panel.hidden {
  opacity: 0;
  transform: translateX(20px);
  pointer-events: none;
}

.room-details-panel h2 {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: var(--spacing-lg);
  color: var(--text-primary);
  padding-bottom: var(--spacing-md);
  border-bottom: 2px solid var(--border-color);
}

.detail-row {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  padding: var(--spacing-md) 0;
  border-bottom: 1px solid var(--border-color);
  gap: var(--spacing-md);
}

.detail-row:last-child {
  border-bottom: none;
}

.detail-label {
  font-weight: 600;
  color: var(--text-secondary);
  font-size: 0.875rem;
  flex-shrink: 0;
}

.detail-value {
  font-weight: 500;
  color: var(--text-primary);
  text-align: right;
  word-break: break-word;
}

.access-code {
  font-family: 'Courier New', monospace;
  font-size: 1.125rem;
  font-weight: 700;
  color: var(--primary-color);
  background-color: #eff6ff;
  padding: 0.25rem 0.5rem;
  border-radius: var(--radius-sm);
}

.guest-info {
  margin-top: var(--spacing-md);
  padding-top: var(--spacing-md);
  border-top: 2px solid var(--border-color);
}

.guest-info.hidden {
  display: none;
}

.action-buttons {
  display: flex;
  gap: var(--spacing-md);
  margin-top: var(--spacing-xl);
  padding-top: var(--spacing-lg);
  border-top: 2px solid var(--border-color);
}

.action-buttons .btn {
  flex: 1;
}

/* ===========================
   Badge Styles (Code Status)
   =========================== */

.badge {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-xs);
  padding: 0.25rem 0.75rem;
  border-radius: var(--radius-md);
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.025em;
}

.badge.used {
  background-color: #dcfce7;
  color: var(--success-color);
}

.badge.unused {
  background-color: #fef3c7;
  color: var(--warning-color);
}

.badge::before {
  content: '';
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background-color: currentColor;
}

/* ===========================
   Modal Styles
   =========================== */

.modal {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-color: rgba(0, 0, 0, 0.5);
  backdrop-filter: blur(4px);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1000;
  padding: var(--spacing-lg);
  transition: opacity var(--transition-normal);
}

.modal.hidden {
  opacity: 0;
  pointer-events: none;
}

.modal-content {
  background-color: var(--surface-color);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-xl);
  width: 100%;
  max-width: 500px;
  max-height: 90vh;
  overflow-y: auto;
  animation: modalSlideIn var(--transition-normal);
}

@keyframes modalSlideIn {
  from {
    transform: translateY(-20px);
    opacity: 0;
  }
  to {
    transform: translateY(0);
    opacity: 1;
  }
}

.modal-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: var(--spacing-xl);
  border-bottom: 1px solid var(--border-color);
}

.modal-header h2 {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--text-primary);
}

.close-btn {
  background: none;
  border: none;
  font-size: 2rem;
  color: var(--text-secondary);
  cursor: pointer;
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
}

.close-btn:hover {
  background-color: var(--bg-color);
  color: var(--text-primary);
}

.modal-body {
  padding: var(--spacing-xl);
}

/* ===========================
   Form Styles
   =========================== */

.form-group {
  margin-bottom: var(--spacing-lg);
}

.form-group label {
  display: block;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: var(--spacing-sm);
  font-size: 0.875rem;
}

.form-group input[type="text"] {
  width: 100%;
  padding: 0.75rem 1rem;
  border: 2px solid var(--border-color);
  border-radius: var(--radius-md);
  font-size: 1rem;
  transition: all var(--transition-fast);
  outline: none;
}

.form-group input[type="text"]:focus {
  border-color: var(--primary-color);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.form-group input[type="text"]::placeholder {
  color: var(--text-light);
}

.room-number-display {
  display: inline-block;
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--primary-color);
  background-color: #eff6ff;
  padding: 0.5rem 1rem;
  border-radius: var(--radius-md);
}

.form-actions {
  display: flex;
  gap: var(--spacing-md);
  margin-top: var(--spacing-xl);
}

.form-actions .btn {
  flex: 1;
}

/* ===========================
   Check-in Result Styles
   =========================== */

.checkin-result {
  transition: opacity var(--transition-normal);
}

.checkin-result.hidden {
  display: none;
}

.success-message {
  text-align: center;
  padding: var(--spacing-xl) 0;
}

.success-message h3 {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--success-color);
  margin-bottom: var(--spacing-md);
}

.success-message p {
  color: var(--text-secondary);
  margin-bottom: var(--spacing-lg);
}

.access-code-display {
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  padding: var(--spacing-xl);
  border-radius: var(--radius-lg);
  margin: var(--spacing-xl) 0;
  box-shadow: var(--shadow-lg);
}

.access-code-large {
  font-family: 'Courier New', monospace;
  font-size: 2.5rem;
  font-weight: 700;
  color: white;
  letter-spacing: 0.25rem;
  display: block;
}

/* ===========================
   Notification Toast
   =========================== */

.notification {
  position: fixed;
  bottom: var(--spacing-xl);
  right: var(--spacing-xl);
  background-color: var(--text-primary);
  color: white;
  padding: var(--spacing-md) var(--spacing-xl);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-xl);
  z-index: 2000;
  max-width: 400px;
  animation: slideInUp var(--transition-normal);
  transition: opacity var(--transition-normal);
}

.notification.hidden {
  opacity: 0;
  pointer-events: none;
}

.notification.success {
  background-color: var(--success-color);
}

.notification.error {
  background-color: var(--danger-color);
}

@keyframes slideInUp {
  from {
    transform: translateY(100px);
    opacity: 0;
  }
  to {
    transform: translateY(0);
    opacity: 1;
  }
}

/* ===========================
   Loading Spinner
   =========================== */

.loading-overlay {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-color: rgba(0, 0, 0, 0.3);
  backdrop-filter: blur(2px);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1500;
  transition: opacity var(--transition-normal);
}

.loading-overlay.hidden {
  opacity: 0;
  pointer-events: none;
}

.spinner {
  width: 50px;
  height: 50px;
  border: 4px solid rgba(255, 255, 255, 0.3);
  border-top-color: white;
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

@keyframes spin {
  to {
    transform: rotate(360deg);
  }
}

.btn-loading {
  position: relative;
  color: transparent !important;
  pointer-events: none;
}

.btn-loading::after {
  content: '';
  position: absolute;
  width: 16px;
  height: 16px;
  top: 50%;
  left: 50%;
  margin-left: -8px;
  margin-top: -8px;
  border: 2px solid transparent;
  border-top-color: currentColor;
  border-radius: 50%;
  animation: spin 0.6s linear infinite;
  color: white;
}

.input-error {
  border-color: var(--danger-color) !important;
  box-shadow: 0 0 0 3px rgba(220, 38, 38, 0.1) !important;
}

.error-message {
  color: var(--danger-color);
  font-size: 0.875rem;
  margin-top: var(--spacing-xs);
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
}

.error-message::before {
  content: '⚠';
  font-size: 1rem;
}

/* ===========================
   Utility Classes
   =========================== */

.hidden {
  display: none !important;
}

/* ===========================
   Responsive Design
   =========================== */

/* Tablet (768px and below) */
@media (max-width: 768px) {
  main {
    grid-template-columns: 1fr;
    padding: var(--spacing-md);
  }
  
  header {
    padding: var(--spacing-md);
  }
  
  header h1 {
    font-size: 1.25rem;
  }
  
  .room-grid {
    grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
    gap: var(--spacing-md);
  }
  
  .room-details-panel {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    max-height: 100vh;
    border-radius: 0;
    z-index: 500;
    transform: translateY(100%);
  }
  
  .room-details-panel:not(.hidden) {
    transform: translateY(0);
  }
  
  .action-buttons {
    flex-direction: column;
  }
  
  .action-buttons .btn {
    width: 100%;
  }
  
  .modal-content {
    max-width: 100%;
    border-radius: var(--radius-lg);
  }
  
  .notification {
    left: var(--spacing-md);
    right: var(--spacing-md);
    bottom: var(--spacing-md);
  }
}

/* Mobile (480px and below) */
@media (max-width: 480px) {
  .room-grid {
    grid-template-columns: repeat(auto-fill, minmax(120px, 1fr));
    gap: var(--spacing-sm);
  }
  
  .room-card {
    padding: var(--spacing-md);
  }
  
  .room-number {
    font-size: 1.5rem;
  }
  
  .room-status {
    font-size: 0.75rem;
    padding: 0.125rem 0.5rem;
  }
  
  .access-code-large {
    font-size: 1.75rem;
    letter-spacing: 0.125rem;
  }
  
  .form-actions {
    flex-direction: column;
  }
}

/* Large screens (1400px and above) */
@media (min-width: 1400px) {
  .room-grid {
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  }
}